OK folks,

In the very high and hot summer  temperatures here in Idaho my oil and CHT temps seem to run a little warm creeping up into the yellow range as specified by Rotax.. Last summer I added an  air scoop to the NACA duct for the oil cooler - dropped the temp very slightly, but it did decrease. Also added an air scoop to the radiator (vertical ULS) which again helped slightly. Picture attached.

Now am fabricating a "lip" for the bottom of the cowl to increase - maybe - air flow through the cowl.  Read that this will decrease the pressure at the cowl air exit thus more air flow.

Question - how much lip in height do I want and also should the height of the lip follow all the way around to the juncture of the fire wall??  Attached picture of my rudimentary efforts - please ignore the mess in my shop - the flare and lip will be better finished when done.

Phil Smith

CH 701